Once hijacked, the hacker wrote just two messages from the actor/producer/tech fan's account. The first of which said:

Ashton, you've been Punk'd. This account is not secure. Dude, where's my SSL?

And minutes later:

P.S. This is for those young protesters around the world who deserve not to have their Facebook & Twitter accounts hacked like this. #SSL

The line, "Dude, where's my SSL?" and hashtag #SSL, point out a possible absence of SSL encryption, according to Graham Cluley, a consultant at the IT-company Sophos, who wrote about the Twitter hack on the company's Naked Security blog.

Cluley said in his post that he suspects someone sitting near Kutcher hacked in to the @aplusk account using software called Firesheep, or something similar, to perform what is called a sidehack.

Such a sidehack can take place when two people are using social media apps or websites such as Facebook or Twitter over unencrypted Wi-Fi networks, he noted.

The second tweet during the apparently temporary hack seems to make a reference to the youthful, tech-saavy protesters in Arab countries who've been recently calling for democratic governments in Tunisia, Egypt, Libya, Yemen and other countries -- many of whom have used technology and social media in varying ways to help organize their demonstrations.

Also worth noting for fans of the man married to Demi Moore, the line "Dude, where's my SSL?" looks to be a nod to Kutcher's year-2000 film, "Dude, Where's My Car?" and "you've been Punk'd" is a nudge to the Punk'd series that used to run on the cable network MTV.

Kutcher created the Punk'd TV show, which ran from 2003 to 2007, and in each episode he'd pull pranks on other celebrities, such as towing their cars, staging fake police standoffs in their homes, or ruining their parties and dinners.

The hack took place almost 18 hours ago and, as of about 11:30 a.m. on Thursday, Kutcher had yet to send out any new messages on his Twitter account.